In a network on the basis of IPv6, an IPv6 address which is assigned to a network device connected to the network is 128 bits long. Of them, the first-half 64 bits are allocated to a network prefix included in RA (Router Advertisement) from a router. The second-half 64 bits are allocated to an EUI-64 format interface ID as a 64-bit identifier decided by the IEEE.
In the EUI-64 format interface ID, an MAC address is encapsulated. In 64 bits of the entire interface ID, the former 24 bits are allocated to a number indicating a manufacturer administrated by the IEEE, the next 16 bits are allocated to “FFFE”, and the latter 24 bits are allocated to an expanded identification number managed by a manufacturer.
The IPv6 address allocated in this manner ensures uniqueness in that the MAC address encapsulated in the interface ID is not overlapped and a unique number.
When a network device (control device) to which the IPv6 address is assigned controls another network device (controlled device), identification information of the controlled device managed by a database server on a network is referred to control access to the controlled device on the basis of the identification information of the controlled device.
In an IPv6 network system disclosed in Patent Document 1, filtering or high-level services in an IP packet transfer is functionally limited in accordance with a value of an interface ID contained in an IPv6 address of a device connected to a network. Accordingly, security is improved. Moreover, information indicating communication contents or a device attribute is contained in the interface ID, thereby performing communication control corresponding to the relevant attribute.
Patent Document 1: JP-A-2004-289782